Conventional methods for taking high dynamic range images are useful in improving excessive dark parts of an image of undesirably high contrast. However, the conventional methods for taking high dynamic range images entail taking images at different exposure levels before combining the images according to different brightness levels so as to obtain a perfect image. However, the conventional methods have their own drawbacks. Plenty images of the same scene have to be taken of in advance. It is rather difficult to take pictures of the same image at the same scene but at different exposure levels without a tool for holding a camera, such as a camera tripod, not to mention that it is a waste of storage space to store on memory plenty of pictures taken of the same image.
US 2006/0,061,845, entitled Image Composition System and Method, disclosed a system of composing images taken at different exposure levels. The image composition system comprises an image detection unit and an image composition unit. The image detection unit detects marked parts in low dynamic range images. The low dynamic range images are images of the same scene taken at different exposure levels. The image composition unit sets exposure history data of the low dynamic range images according to the marked parts. The image composition unit then synthesizes the low dynamic range images into a high dynamic range image according to the exposure history data. However, the image composition system and method disclosed in US 2006/0,061,845 has its own drawbacks, that is, it is rather difficult to take pictures of the same image at the same scene but at different exposure levels, not to mention that it is a waste of storage space to store on memory plenty of pictures taken of the same image.
The inventor of the present invention realized the drawbacks of the prior art and endeavored to overcome the drawbacks by inventing a method for simulating dark-part exposure compensation of high dynamic range images using a single image and an image processing device for use with the method, wherein excessive dark parts of an image of undesirably high contrast are improved by reference to a single image.